Carburetor



Febl, 1955 F. DE BENr-:nETTl Erm. 2,700,989

CARBURETOR Filed Aug. 12, 1949 United States Patent VO CARBURETOR Francesco De Benedetti and Mario Thiele, Milan, Italy Application August 12, 1949, Serial No. 109,846

Claims priority, application Italy June 6, 1949 3 Claims. (Cl. 13S-46) This invention relates to a carburetor, and more particularly to a choke tube for a carburetor, having a variable cross section and wherein the axis of the ow is not altered.

Our invention aims at a choke tube for a carburetor, which makes it possible that the amount of air be easily adjusted according to the engine speed, the temperature, the atmospheric pressure, and the outside temperature. Also, our invention aims to provide additional air passages, besides the main air passage, thereby furthering a perfect carburetion, with the results of an increase in engine efciency and a reduction of fuel consumption.

In order that our invention may be fully understood, illustrative embodiments are hereinafter described in detail, merely by way of example, and shown in the accompanying drawing wherein:

Fig. 1 is an elevational view, in section, of a part of a choke tube, or the choke tube proper, according to the invention;

Fig. 2 is a sectional elevation of a part to be associated with the part of Fig. 1, the former part forming a regulating member;

Fig. 3 is a plan view of the part shown in Fig. l;

Fig. 4 is a cross sectional view of the cooperating parts of Figs. 1 and 2, illustrating the position of maximum sectional area;

Fig. 5 is a view similar to that of Fig. 4, illustrating the minimum sectional area;

Fig. 6 is a sectional view of a modified choke tube;

Fig. 7 is a bottom end view of the tube of Fig. 6;

Fig. 8 is a plan view of the regulating member to be used with the part of Figs. 6 and 7; and

Fig. 9 is a sectional perspective view of a carburetor equipped with the tube of Figs. 6 and 7 and the control member of Fig. 8

Referring to the drawing in greater detail, the choke tube of Fig. l forms a ring-shaped member designated 1, which is interiorly provided with a plurality of protruding ribs 2. These ribs taper toward the outlet end of the choke tube, which is the upper end in the drawing. Between the ribs are grooves 3 (see Fig. 3). The member 4 shown in Fig. 2, likewise ring-shaped, is adapted to be introduced within the ring 1. The ring 4 is provided with upwardly extending extensions 5 which, when viewed in cross section, have L-shape, and which bend into the upward direction at 5" (see Figs. 2, 4 and 5). The offset flange of the main portion of the extensions is identified by 5. The extensions are shaped, as can be seen from Fig. 5, to fit within the grooves 3. The member 4 is provided with an actuating stud 25 by means of which the member 4, when placed within the member 1, can be rotated in either direction about the common axis of the two members. By rotating the ring 4, the extensions 5 may be moved from the position of Fig. 4 to the position of Fig. 5, or vice versa.

From inspection of Fig. 4 it will be seen that the whole area shown in Fig. 3, and consisting of the central passage A and additional passages B, is open to the passage of air. In the position of Fig. 4, the extensions 5 of the ring 4 overlie the ribs 2 of the ring 1. When the ring 4 is brought into the position of Fig. 5, the extensions 5 no longer lie over the ribs 2 but extend across the grooves 3 and separate the additional passages formed by the grooves 3 from the central passage. The grooves ice 3 being shut, no air passes therethrough, so that in the position of Fig. 5 the area open to the passage of air is the area of Fig. 3 or Fig. 4 minus the areas of all the grooves 3. With the extensions 5 overlying the grooves 3 (Fig. 5), the curved portions 5 of the extensions close the openings to the grooves, thus leaving the central passage only open to the air flow. g f

The body 11 of the choke tube shown in Figs. 6 and 7 has a substantially cylindrical outside surface and a double-cone inside surface. There arelongitudinally extending grooves 23 in the outside surface which merge into inwardly directed channels 24. Fig.`9 shows that the grooves 23 which form parts of the additional passages are conned by the tube 11 and the envelope 27. The grooves 23 correspond to the cutouts 29, as they appear when viewed from the bottom (see Fig.y 7). The teeth 29' of the control member 28 (see Fig. 8) are to register with the cutouts 29 to close the additional passages. When the recesses 30 of the control member register with the cutouts 29 of the tube 11, the additional passages are open.

It is believed that my device and the many advantages thereof will be fully understood from the foregoing description. It will be apparent that the construction of my choke tube may be adapted to the type of carburetor to which the tube is to be applied since the grooves or channels to serve as additional passages may be provided in many different ways. One of the cooperating parts of my device is preferably stationary and connected to the carburetor, whereas the other part is rotatably arranged to act like a valve or cock. One advantage offered by our invention is that our choke tube is applicable to existing carburetors. The control member may be automatically or hand operated.

It will also be apparent that while we have shown and described our invention in two forms only, many changes and modifications may be made without departing from the spirit of the invention defined in the following claims.

What I claim is:

l. Carburetor provided with a main air passage and additional air passages, including two coaxially arranged bodies, said bodies being rotatable relatively to each other, one of said bodies being of cylindrical and annular shape and being interiorly and alternatingly' provided with ribs and grooves, said body defining interiorly said main passage and said additional passages, said ribs tapering toward the air outlet, the other body being ringshaped and being provided with as many, circumferentially arranged and parallel to the axis of said other body, extending members as corresponds to the number of ribs or grooves formed between the ribs, said members being shaped to overlap said ribs to keep the additional air passages open, and, upon rotation, to extend across said grooves to close the additional air passages.

2. Carburetor including at least two bodies arranged to be coaxial and in abutting relation and rotatable relative to one another, one of said bodies being substantially of tubelike shape and defining both an axially extending central main air passage and additional circularly arranged air passages, the other body being substantially ringshaped and being circularly and alternatingly provided with recesses and projections to successively and progressively register with the additional passages during relative rotation of the said bodies, the recesses opening, and the projections closing, the additional passages.

3. Carburetor including two bodies coaxially and rotatably arranged relative to one another, one of said bodies being substantially of hollow cylindrical shape, the inner surface of the wall of said body narrowing intermediate the ends of the body and defining an axially extending central or main air passage restricted in said narrowed portion, said body being intermittently and exteriorly provided with grooves extending from one end of the body only part-way toward the other end, the body being also provided with channels, each leading from the inner end of a groove through the wall of the lbody to the inner wall surface, the other body being ring-shaped and being circularly and intermittently provided with passageways adapted to register with said channels at their outer ends, portions of the second named body between the passageways closing the channels when the passageways do not register with the channels, the grooves and continuation channels forming additional air passages, said additional air passages being, respectively, progressively opened and progressively closed during relative rotation of the two bodies.

References Cited in the le of this patent UNITED STATES PATENTS Nelson Apr. 19, 1927 Jensen Dec. 10, 1929 Austin Mar. 25, 1930 Johnston et al Jan. 9, 1940 

